Electro-acoustic transducers and devices that incorporate them are becoming ever more widely used at an ever increasing rate. Technological advances have increased the amount of voice, video, music and other audio-visual material that can be stored within both portable and stationary devices; have increased the fidelity with which voice and video are able to be conveyed between persons in two-way communications; have increased the effectiveness with which active noise reduction (ANR) capabilities can be provided by a portable device; and have increased the flexibility that can be provided to end users to manipulate audio-visual material as it is played. As a result, not only has the quantity of devices incorporating electro-acoustic transducers dramatically increased, but so has the expectations of end-users regarding the quality of those devices.
By way of example, not just the quantity of personal digital audio players has increased, but also end user expectations of being able to hear the audio played by these devices with a fuller range of frequencies and greater clarity, even when listening with what might otherwise be viewed as a “simple” pair of headphones. By way of another example, not just the quantity of home theatre systems capable of providing a sought-after “movie like” experience has increased, but also user expectations of the quality of the audible illusion of “being there” in the scenery displayed on a screen as provided by an ever increasing quantity and types of acoustic drivers positioned around an end user's listening space. By way of yet another example, not just the quantity of personal ANR headsets has increased, but also user expectations of the completeness of the noise reduction effect to enable them to “shut out” (i.e., attenuate) unwanted sounds in their environment.
With this fast developing situation, overcoming inevitable variances in the characteristics of electro-acoustic transducers, from one to another of any given manufacturing run and from sought-after ideal characteristics, is becoming ever more important. A longstanding practice to accommodate such variances has been testing a specific electro-acoustic transducer to discern its characteristics, and then tuning a gain control component within a device to compensate for how those characteristics differ from sought-after ideal characteristics. Taking this step in the manufacture of such a device may successfully bring the resulting behavior of that electro-acoustic transducer closer to a sought-after ideal, but the effectiveness of this step can later be entirely undermined where that electro-acoustic transducer or that previously tuned gain control component is replaced such that there ceases to be such a match between an electro-acoustic transducer and a gain control component.
Correcting this later introduction of such a mismatch between an electro-acoustic transducer and the tuning of a gain control component usually involves bringing the device to a location at which appropriately trained personnel with access to appropriate equipment are able to perform the same type of testing of the electro-acoustic transducer and tuning of the gain control component that was originally done as part of the manufacture of the device to create a new such match. Alternatively, where it is the electro-acoustic transducer that is being replaced, correcting such a later occurring mismatch could involve testing a multitude of candidate replacement electro-acoustic transducers in the hope of finding one having characteristics close enough to the one being replaced that another tuning of a gain control component is rendered unnecessary.